Open AccessVertical profiles and horizontal transport of atmospheric aerosols and trace gases over central Ontario
Author(s) -
Isaac G. A.,
Banic C. M.,
Leaitch W. R.,
Anlauf K. G.,
Couture M. D.,
Liu P. S. K.,
Macdonald A. M.,
MacQuarrie K. I. A.,
Puckett K. J.,
Wiebe H. A.
Publication year - 1998
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98jd01727
Subject(s) - aerosol , trace gas , environmental science , atmospheric sciences , particulates , nitrate , spring (device) , mixing ratio , hydrology (agriculture) , meteorology , geology , chemistry , geography , mechanical engineering , organic chemistry , engineering , geotechnical engineering
The Canadian intensive measurement periods of the Eulerian Model Evaluation Field Study (EMEFS) were conducted in the summer of 1988 and the spring of 1990 in central Ontario, Canada. The project involved using instrumented research aircraft to measure vertical profiles of atmospheric aerosols and trace gases over special ground observing sites. Oxidant concentrations were often highest aloft. There were no strong diurnal variations in O 3 and H 2 O 2 , suggesting that oxidant concentrations reported in this paper, as well as other species, seem to be most influenced by transport mechanisms rather than local chemical transformations. Aerosol and SO 2 concentration vertical profiles tended to be similar to those of water vapor mixing ratio, showing a maximum near the surface, which points to a ground level source for these constituents. The inorganic aerosol was dominated by sulphate during the summer measurements, but particulate nitrate was important during the spring. The horizontal transport of these species was calculated for air with back trajectories from the north or south, showing transport to occur primarily from west to east for both cases, with components to the south or north, respectively. The sulphur is transported primarily as SO 2 in the spring and about half as SO 2 and half as SO 4 = in the summer. Air from the south is a source of particles, S, H 2 O, O 3 , H 2 O 2 and NO 2 to this region. Similarly, cloud water concentrations of sulphate and nitrate were higher with southerly trajectories, as were aircraft filter measurements of sulphate, nitrate, ammonium, and nitric acid.